Field of the Invention
The present invention relates to a processing method of a silicon substrate, in which a through port is formed in a silicon substrate by etching, and further, relates to a fabricating method of a substrate for a liquid ejection head by using the processing method, and a fabricating method of a liquid ejection head.
Description of the Related Art
A fine structure obtained by processing silicon is widely used in the fields of MEMS or a mechanism device for an electric machine. The fine structure is exemplified by a liquid ejection head for ejecting liquid. Examples of devices using the liquid ejection head for ejecting liquid include an ink jet print head for use in an ink jet print system for ejecting ink onto a print medium, followed by printing. The ink jet print head is provided with a substrate having an energy generating element for generating energy to be utilized for ejecting liquid (i.e., ink) and an ejection port, through which the ink supplied from a liquid supply port formed in the substrate is ejected.
U.S. Pat. No. 6,679,587 discloses a fabricating method for the above-described ink jet print head, in which etching is performed in a state in which a mask is incorporated in a silicon substrate. In this method, first, a mask having a penetration pattern for processing a supply port, formed thereat is held between two silicon substrates (i.e., a first silicon substrate and a second silicon substrate). Next, an opening pattern for processing a common liquid chamber is formed at the reverse of the first silicon substrate. Thereafter, as the common liquid chamber is being processed by dry etching at the reverse of the second silicon substrate, the previously held mask for the supply port appears. The supply port is further etched via the pattern formed on the mask, thus forming a through port including the common liquid chamber and the supply port.
In addition, Japanese Patent Laid-Open No. 2011-161915 discloses a fabricating method for enhancing the formation accuracy of a supply port in the fabricating method disclosed in U.S. Pat. No. 6,679,587.